Specific Process Knowledge/Lithography/Aligners/Aligner: Maskless 02 processing: Difference between revisions
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==Writing speed== | ==Writing speed== | ||
According to specs, the writing speed of Aligner: Maskless 02 is 1200 mm<sup>2</sup>/min in fast mode. Using the high quality exposure mode cuts this speed by 2.5, to approximately 480 mm<sup>2</sup>/min. The writing speed for a 100x100 mm<sup>2</sup> area measured after being modified to write mode 2 tool (2023-03-21) of the machine was ~1200 mm<sup>2</sup>/min. | According to specs (after being converted to write mode 2), the writing speed of Aligner: Maskless 02 is 1200 mm<sup>2</sup>/min in fast mode. Using the high quality exposure mode cuts this speed by 2.5, to approximately 480 mm<sup>2</sup>/min. The writing speed for a 100x100 mm<sup>2</sup> area measured after being modified to write mode 2 tool (2023-03-21) of the machine was ~1200 mm<sup>2</sup>/min. | ||
[[Image:MLA150_speedVSarea.JPG|400x400px|thumb|The writing speed of Aligner: Maskless 02 (fast mode, 375nm) as a function of the exposure area]] | [[Image:MLA150_speedVSarea.JPG|400x400px|thumb|The writing speed of Aligner: Maskless 02 (fast mode, 375nm) as a function of the exposure area]] | ||
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'''Speed vs. area:''' | '''Speed vs. area:''' | ||
During exposure of a stripe the stage moves at a constant speed. Each stripe thus includes a certain movement overhead for acceleration and deceleration. As the stripes get shorter, this overhead becomes more significant, and the normal writing speed is no longer achieved. For samples smaller than a 2" wafer, the writing speed of Aligner: Maskless 02 drops below the specified | During exposure of a stripe the stage moves at a constant speed. Each stripe thus includes a certain movement overhead for acceleration and deceleration. As the stripes get shorter, this overhead becomes more significant, and the normal writing speed is no longer achieved. For samples smaller than a 2" wafer, the writing speed of Aligner: Maskless 02 drops below the specified 1200 mm<sup>2</sup>/min. | ||
When the exposure is started on the maskless aligner, the software starts converting the design to the | When the exposure is started on the maskless aligner, the software starts converting the design to the image files needed for the exposure. When sufficient data has been generated, the hardware starts exposing the sample, while more image data is being generated in the background. This simultaneous data conversion and exposure is called Online conversion. Once a design has been converted (and/or exposed) the data may be reused for repeated exposures. Due to no time lost waiting for data conversion, offline exposure may be several tens of % faster than online. However, the converted data can only be reused if no alignment is needed, including flat alignment ("Expose with substrate angle"/"Expose with Global Angle"). | ||
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[[Image:MLA150 speedVSdose.JPG|400x400px|thumb|The writing speed of Aligner: Maskless 02 as a function of the exposure dose]] | [[Image:MLA150 speedVSdose.JPG|400x400px|thumb|The writing speed of Aligner: Maskless 02 as a function of the exposure dose - OBSOLETE: write mode 1 writing speed]] | ||
'''Speed vs. dose:''' | '''Speed vs. dose:''' | ||
The writing speed remains almost constant up to a dose of | The writing speed remains almost constant up to a dose of 1000 mJ/cm<sup>2</sup>. The writing speed is 50% at a dose of 4500 mJ/cm<sup>2</sup>. | ||
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'''Speed vs. design:''' | '''Speed vs. design:''' | ||
Depending on the complexity and density of the pattern, the conversion process may slow down the exposure significantly. A | Depending on the complexity and density of the pattern, the conversion process may slow down the exposure significantly. A 100 mm wafer exposed with a pattern consisting of 200 million 5 µm circles took 65 minutes (154 mm<sup>2</sup>/min), compared to the specified 35 minutes (285 mm<sup>2</sup>/min). It took 12 minutes before the first stripe was exposed. | ||
The maskless aligner exposes the design in north-south oriented stripes (perpendicular to the flat). The stripes all have the same length, set by the height of the design, and only completely empty stripes are skipped. The writing speed may thus be affected by the layout of the design, as shown below. | The maskless aligner exposes the design in north-south oriented stripes (perpendicular to the flat). The stripes all have the same length, set by the height of the design, and only completely empty stripes are skipped. The writing speed may thus be affected by the layout of the design, as shown below. | ||